The present invention relates to windscreen-wiper blades for motor vehicles and similar applications, of the type comprising a holder of moulded plastics material constituted by a main bow whose convex side has a central portion for attachment to an operating arm and whose concave side carries at least two secondary bows, and a wiper blade of elastomeric material carried by a longitudinal support which is inserted between pairs of lateral retaining claws on the main bow and the secondary bows.
More particularly, the invention relates to a windscreen-wiper blade of the type defined above, in which the secondary bows are formed in a single piece with the main bow.
A windscreen-wiper blade of this type is known from GB-B-1078066, according to which the support for the wiper blade is free to slide longitudinally through the retaining claws. This freedom to slide is necessary to allow the blade holder to bend resiliently in order to adapt itself to the shape of the surface to be wiped but involves the risk of the support and the wiper blade accidentally coming out of the blade holder, or at least being displaced from their correct central position therein.
The object of the present invention is to avoid this problem and to provide a windscreen-wiper blade of the type defined above which is formed so as to ensure that the support and the wiper blade are centered correctly in the blade holder.
A further object of the invention is to prevent the support and the wiper blade from accidently coming out of the blade holder longitudinally.
A further object of the invention is to provide a windscreen-wiper blade of the type defined whose blade holder can easily be manufactured as a unit by a single moulding operation and which also enables the support with its wiper blade to be fitted in a fully automated manner without manual intervention.
The windscreen-wiper blade according to the invention is characterised mainly in that the main bow of the blade holder has two integral transverse centering and stop projections which project from its ends on the same side as the secondary bows to prevent the the support of the wiper blade from coming out of the blade holder longitudinally.
According to another aspect of the invention, the attachment portion of the main bow of the blade holder includes a transverse fixing pin integral with the main bow.
To advantage, the pairs of lateral retaining claws are also integral with the main bow and the secondary bows respectively, the claws of each pair being offset from each other longitudinally. This arrangement simplifies the moulding of the blade holder.
According to another aspect of the invention, at least for most of its length, the main bow has a channel-shaped cross-section whose cavity is on the convex side of the bow. This configuration affords the blade holder good resistance to the torsional forces to which the blade is subject in use.
A further subject of the invention is a method of manufacturing the windscreen-wiper blade defined above which enables the fully automated assembly of the support with its wiper blade and the holder.
The method comprises the following steps:
moulding the main bow together with the secondary bows, the fixing pin, the retaining claws and the transverse centering and stop projection at one end of the main bow from a thermoplastics material, the transverse stop projection at the other end of the main bow being moulded so as to project from the side opposite the secondary bows, PA1 providing and interconnecting the longitudinal support and the wiper blade, PA1 inserting the longitudinal support between the lateral claws from the said other end of the main bow, PA1 shifting the other stop projection so that it projects from the same side as the secondary bows.
Conveniently, the other stop projection is transferred ultrasonically.